rpms/kernel
9
2
Fork 4
Code Issues Pull Requests Releases Activity

Yet another KPTI fix

Browse Source
This commit is contained in:
Laura Abbott 2018-01-03 14:22:54 -08:00
parent 72b9cb4f82
commit b23e66e346
2 changed files with 77 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
kernel.spec
View File

@ -42,7 +42,7 @@ Summary: The Linux kernel
# For non-released -rc kernels, this will be appended after the rcX and
# gitX tags, so a 3 here would become part of release "0.rcX.gitX.3"
#
%global baserelease 2
%global baserelease 3
%global fedora_build %{baserelease}
# base_sublevel is the kernel version we're starting with and patching
@ -2201,6 +2201,9 @@ fi
#
#
%changelog
* Wed Jan 03 2018 Laura Abbott <labbott@redhat.com> - 4.15.0-0.rc6.git0.3
- Yet another KPTI fix
* Wed Jan 03 2018 Laura Abbott <labbott@redhat.com> - 4.15.0-0.rc6.git0.2
- KPTI Fix

73
kpti-fix.patch
View File

@ -54,3 +54,76 @@ index bce8aea..2da28ba 100644
--
cgit v1.1
From fea692ec9308084475c0c93bf74bcb2a35f3d417 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 3 Jan 2018 19:52:04 +0100
Subject: [PATCH] CONFIG_PAGE_TABLE_ISOLATION=y on x86_64 causes gcc to
segfault when building x86_32 binaries
On Wed, 3 Jan 2018, Thomas Gleixner wrote:
> On Wed, 3 Jan 2018, Lars Wendler wrote:
> > Am Wed, 3 Jan 2018 13:05:38 +0100 (CET)
> > schrieb Thomas Gleixner <tglx@linutronix.de>:
> > > Also can you please try Linus v4.15-rc6 with PTI enabled so we can see
> > > whether that's a backport issue or a general one?
> >
> > Same problem with 4.15-rc6. So I suppose that means it's a general
> > issue.
>
> Just a shot in the dark as I just decoded another issue on a AMD CPU. Can
> you please try the patch below?
Ok. Found the real issue. This is a problem on AMD boxen.
Fix below.
Can Xen folks please have a look at that as well?
Thanks,
tglx
8<-------------------
arch/x86/entry/entry_64_compat.S | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
---
arch/x86/entry/entry_64_compat.S | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 40f17009ec20..4c4b9545b848 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -190,8 +190,13 @@ ENTRY(entry_SYSCALL_compat)
/* Interrupts are off on entry. */
swapgs
- /* Stash user ESP and switch to the kernel stack. */
+ /* Stash user ESP */
movl %esp, %r8d
+
+ /* Use %rsp as scratch reg. User ESP is stashed in r8 */
+ SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
+
+ /* Switch to the kernel stack */
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/* Construct struct pt_regs on stack */
@@ -219,12 +224,6 @@ GLOBAL(entry_SYSCALL_compat_after_hwframe)
pushq $0 /* pt_regs->r14 = 0 */
pushq $0 /* pt_regs->r15 = 0 */
- /*
- * We just saved %rdi so it is safe to clobber. It is not
- * preserved during the C calls inside TRACE_IRQS_OFF anyway.
- */
- SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
-
/*
* User mode is traced as though IRQs are on, and SYSENTER
* turned them off.
--
2.14.3